The present invention relates to a retainer assembly and method for axially fixing a splined hub on a splined shaft. More specifically, the present invention relates to a novel retainer ring and groove assembly used to secure a splined shaft and splined hub in a constant velocity joint.
The present invention relates to an improved retainer system and method of assembly for use in connection with attaching a splined shaft with a splined hub. The primary use for the invention is in connection with constant velocity joints in vehicles.
Typically such joints include a halfshaft bar. This halfshaft has ends that are splined and grooved male type ends. The halfshaft is typically connected to an inboard joint and an outboard joint, as is well known in the art. The inboard and outboard joints may take any well-known design, such as for example, a Rzeppa joint or a Tripot joint. Each of these designs contains an inner hub that has a female splined portion for receiving the splined half shaft. As with the male splined shaft, the female splined hub includes a groove. The grooves on the hub and on the splined shaft receive a retaining ring for securing the shaft in the hub to prevent axial movement therebetween.
Currently, the retaining ring designs include a double ring design for use in the Tripot type joint, the spot face design for use in a Rzeppa type joint and a buried ring design.
The double ring design as shown, for example, in U.S. Pat. No. 4,516,957 to Chyz et al requires a groove in the torque zone of the splined shaft, which can reduce torsional fatigue life.
The spot face design requires a spot face geometry on the inner race, which is an added expense and a groove in the torque zone of the splined shaft as described above.
The buried ring design solves some of the above problems but the ring groove is positioned in the middle of the spline engagement creating an interrupted spline condition. The buried ring design also causes an assembly problem due to the deep groove geometry on the splined shaft. The deep groove also causes fabrication problems in connection with the heat treatment necessary to produce the splined shaft.
According to the present invention, there is provided a retainer for the interior assembly of a universal joint comprising a shaft having a splined portion and having an external groove. The groove includes a flared wall surface extending at an angle relative to the splined portion and a bottom surface extending from the flared wall surface. The retainer further includes a hub member defining a bore having splines. The hub member is adapted for mating engagement with the splined portion of said shaft. The hub member defines an internal groove including a flared wall extending outwardly from the bore at an angle relative thereto and an annular groove portion extending from the flared wall. The retainer further includes a retaining ring. The retaining ring has first and second legs that are flexible with respect to each other. The first leg engages the flared wall surface of the shaft. The second leg engages the flared wall of the hub to thereby prevent relative axial movement between the hub and the shaft.
A method of inserting a splined shaft into a splined hub is also provided. The method comprises the steps of providing a shaft having a splined portion thereon and an external groove outward of the splined portion. The method further includes the step of providing a hub member defining a bore and having splines. The hub includes an internal groove outward of the splines. A retaining ring having first and second legs is placed into the internal groove of the hub such that the second leg depends downwardly therefrom and into the bore.
The shaft is inserted into the hub member such that the splined portion of the shaft fully engages the splines of the bore prior to engagement of the retaining ring in the external groove of the shaft. The shaft is further inserted into the hub such that the shaft engages the first leg of the retaining ring and deflects the first leg relative to the second leg. Insertion of the shaft is continued until the first leg engages the external groove of said shaft.
It is an object of the present invention to move the retaining ring outboard of the splined area of both the shaft and hub and thus out of the torque zone.
It is another object of the present invention to provide a retainer that allows for spline engagement between the shaft and hub before the retaining ring engages.
It is another object of the present invention to allow for full spline engagement (with no interrupt) between the splined shaft and hub.
It is another object of the present invention to provide relatively shallow groove geometry to eliminate manufacturing problems particularly associated with heat treatment.
It is another object of the present invention to provide a retaining ring design that eliminates the problem of ring droop (which can occur during assembly).
It is another object of the present invention to provide a retaining ring design that allows for disassembly at a predefined load, allowing the retaining ring to sheer into two or more pieces without causing damage to the grooves.